I absolutely love Lego games and I thoroughly enjoyed Lego Lord of the Rings and look forward to Lego The Hobbit.
I have only ever played Lego games on a console however, both PS2 and Xbox 360, and I find the controls enjoyable on them and easy. Controls don't change much if at all between Lego games, so once you've learnt one you've learnt them all.
My friend who purchased Lego LOTR on the PC however did complain that the controls are very annoying and difficult.
I'm not sure if the PC version is a port of the console version or not, but eitherway it doesn't translate too well.
He decided he had to purchase a PC-connectable console controller to play, and since then he's thoroughly enjoyed it.
I think the games are a lot of fun, and LOTR in particular is very entertaining.
It's luckily from the new generation of Lego games where they use voice acting, which is a godsend if you've never read or watched LOTR (Although I'm pretty sure you have :P). It's really tricky to understand what is going on in a Lego game with just minifigure gestures if you don't know the story, which I learnt while playing Lego Star Wars 3.
LOTR does use clips taken from the movies. These aren't brilliant at all times, since there is obviously a limited number of clips they can use and Lego often add in wacky comedy bits, as well as changes to the storyline to allow their game play to work. So you may find a number of voice clips get reused or used in unusual places.
The game has a large number of collectibles and funny items.
A lot of them you'll find are just to be wacky, but most of them grant all characters an ability they don't normally have, when using that character in Free Play or on the Middle Earth hub.
For example, Sam gets Elven Rope from Galadriel in Fellowship, and he uses it to climb up grapple points and pull objects. No other characters can do this until you find other items, like a Mithril Rope (which you make) or a toy snake.
By the end of the game you can go around as any character and do pretty much anything with him, whereas you'd need a specific character before.
There are a lot of things you need to do to fully complete the game, which includes playing all missions once, and then going back in free-mode where you can use characters and items not actually available in that mission (for example, play as Legolas for his bow when in the Black Marsh, where it's just Sam, Frodo and Gollum).
And then use those abilities of other characters to collect Letters (for recipes for making Mithril items), Treasure Chests (To create a mini-kit build of a mission), and special items (usually wacky things, like a giant stop sign weapon, or a mushroom crown).
On top of that you then have Middle Earth (although quite shrunk down, yet still large. [You can see Isengard from Gondor]) to explore and complete little puzzles to collect Mithril Bricks (for making items) and complete quests for NPCs, which consist of finding a special item from a main story mission.
I've probably just described the entire game (I think I did actually).
It's very fun, entertaining, funny, a bit childish but true to the story, and it retains the theme of LOTR and the wack Lego style all throughout.
There's lots to do and explore and find, and you'll keep playing for ages.
For an idea of how long it took to complete, I got the game for Christmas 2012.
I had it on Xbox and I have 2 brothers I have to share the Xbox with, and I have College to occupy me and other games I also played, so I didn't get to play it constantly.
I completed it fully by September 2013. I had probably spent enough time to finish the story first-time round by February, having spent maybe a good 24-ish hours on it.
That left me at quite a small percentage of completion.
The game can take quite a while, but I found it endearing till the end.
